Treatment ResistAnt Depression Subcallosal CingulatE Network DBS (TRANSCEND)

Inclusion Criteria:

1. The patient must be diagnosed with non-psychotic unipolar Major Depressive Disorder.

2. The patient must be in a major depressive episode for ≥12 months or have had atleast 3 lifetime depressive episodes.

3. The patient has tried and failed a minimum of four different types of antidepressanttreatments as measured by a tool designed for this purpose.

4. Depression medication and treatment regimen must be stable for a minimum of 4 weeksbefore the first baseline visit

Exclusion Criteria:

1. Pregnant or those who plan to become pregnant during study

2. Presence of other anatomic or comorbid conditions, or other medical, social, orpsychological conditions that could limit participation in the study or interferewith adherence to the study protocol.

3. Current or lifetime history of psychotic features in any Major Depressive Episode.

4. Has an intracranial Central Nervous System disease that impairs motor, sensory orcognitive function or that requires intermittent or chronic medication.

5. Significant acute suicide risk.

6. Diagnosis of Substance Use Disorder or Alcohol Use Disorder without sustainedremission (12 months or longer).

7. Current and ongoing use of neurostimulation treatment that may interfere with DBStherapy/system.

8. Treatment with another investigational device or investigational drugs.